This application is a national stage filing under 35 U.S.C. xc2xa7371 of PCT International application PCT/US99/20929, filed Sep. 10, 1999, which was published in English under PCT Article 21(2).
Foreign priority benefits are claimed under 35 U.S.C. xc2xa7119(a)-(d) or 35 U.S.C. xc2xa7365(b) to French application number 98/11332, filed Sep. 11, 1998.
1. Field of the Invention
The present invention relates to an implantable prosthesis, and more particularly to a prosthesis for repairing a hernia.
2. Description of the Related Art
A defect in a muscle or tissue wall, such as a hernia, is commonly repaired with an implantable prosthesis that is configured to cover and/or fill the defect. In many instances, a flat sheet of an implantable, non-resorbable, flexible mesh material, such as BARD MESH, has been employed for the parietal repair of hernias and eventrations of the abdominal wall. However, a surgeon may experience some difficulty positioning the mesh between the parietal peritoneum and the abdominopelvic wall. The mesh may also fold or wrinkle and be difficult to maintain in position.
Applicant previously developed an implantable prosthesis for repairing a defect in a muscle or tissue wall to alleviate some of these concerns. The prosthesis, which is disclosed in WO 95/07666 and is assigned to C. R. Bard, the assignee of the present application, is made of an implantable, nonabsorbable and flexible material that is formed to independently assume a curved shape adapted to conform to the anatomical shape of the wall. The prosthesis includes a body comprised of a first portion formed in the shape of a cap and a second portion having a substantially spherical shape connected to a lower edge of the first portion. The second portion has a radius of curvature that is less than the radius of curvature of the first portion. The second portion includes an outer edge that meets the lower edge of the first portion at the apex of the body, which is the highest point of the curved prosthesis.
This prosthesis has proven useful and has become established in the practice of muscle or tissue wall repair in the inguinofemoral region. The prosthesis is not subject to stresses when deformed and, therefore, has no tendency to shift upon implantation. The prosthesis reinforces the abdominal wall at the anatomical region of concern.
It has nevertheless been observed that the reinforcement of the abdominal wall offered by the prosthesis could be extended.
It is an object of the present invention to provide an improved prosthesis for repairing a defect in a muscle or tissue wall by configuring the prosthesis with regard to certain anatomical zones.
The present invention is an implantable prosthesis for repairing a defect in a muscle or tissue wall. The prosthesis includes a body of prosthetic material having a preformed three-dimensional contoured shape that independently assumes a curved shape adapted to conform to the wall. The body is configured to adapt to the inclination of the external iliac vessels to facilitate a desired placement of the prosthesis when employed for repairing an inguinal hernia.
According to one embodiment of the invention, the body includes a first portion with a first lower edge and a second portion with a second outer edge, the second portion being connected to the first portion at the first lower edge. The first portion is configured to have a shape of a cap and the second portion is configured with a substantially spherical shape. The first portion has a first radius of curvature and the second portion has a second radius of curvature that is less than the first radius of curvature. The second outer edge and the first lower edge meet at an apex of the body, the second outer edge forming an angle with the first lower edge that is greater than approximately 100xc2x0 at the apex.
According to one aspect of the invention, the angle is between approximately 101xc2x0 and approximately 120xc2x0.
According to another aspect of the invention, the first portion includes a first outer edge and the second portion includes a second outer edge, and the body further includes a third portion with a third lower edge and a fourth portion. The third portion is connected to the first outer edge and the fourth portion is connected to the third lower edge and to the second outer edge.
A depression may be formed between the second and fourth portions which is configured to be placed proximate the external iliac vessels when the prosthesis is positioned on a wall to repair an inguinal hernia. The angular orientation between the first lower edge and the second outer edge and the depression between the second and fourth portions are adapted to the inclination of the external iliac vessels to facilitate placement of and to minimize shifting of the prosthesis when positioned on the wall. The angular orientation and the depression also provide a degree of deformation for matching adjacent contours.
According to a further aspect of the invention, the prosthesis is configured with a ratio of the surface area of the third portion to the total surface area of the prosthesis from approximately 0.25 to approximately 0.40.
According to still another aspect of the invention, the third portion has a third radius of curvature that is substantially equal to the first radius of curvature along the first outer edge. This configuration reduces the incidence of wrinkles or folds occuring between the first portion and the third portion so that the first and third portions do not partially cover each other upon or after implantation, thereby ensuring that the overall size of the prosthesis is sufficient to adequately cover the desired portion of the wall.